1. Field of the Invention
The present invention relates to a tension mechanism for an .alpha. belt drive apparatus which is spanned along a carriage in order to drive this by a drive pulley.
2. Description of the Prior Art
An .alpha. belt has been utilized as a carriage feeding belt to slide a carriage along a frame carrying a head which makes contact with a disk such as a micro-floppy disk or the like to perform read/write of data since the .alpha. belt provides a positive travel of the carriage in a limited space and is capable of designing a small size apparatus.
The carriage includes a belt receiving portion which connects two ends of the .alpha. belt being wound around the drive pulley, the rotation of which is converted into reciprocating motion of the carriage by the .alpha. belt.
In order to have the .alpha. belt to be properly spanned over the carriage a tension force must be applied to one side of the belt at least. In the prior art, as shown in FIG. 1, the one end of the .alpha. belt 14 is fixed to the carriage 10 with winding around the drive pulley 12, and the other end of the .alpha. belt 14 is connected with the carriage 10 via a coil spring 16. On the other hand, as shown in FIG. 2, a tension spring with U-shape is provided in stead of the coil spring 16 mentioned above. The coil spring 16 or the tension spring 18 are applied as the tension force so that the .alpha. belt 14 can be properly spanned over the carriage 10.
In the prior art device as is mentioned in the above, however, it is hard for the .alpha. belt 14 to be assembled with the carriage 10 since the spring member of the coil spring 16, the tension spring or the like is connectedly provided together with the .alpha. belt 14.